1 Corinthians 9:16

For though I preach the Gospel, I have nothing to glory
of
The sense is not, that if he preached the Gospel in order for a livelihood, and to serve his private advantage, he should have no room for glorying; since, if this was the case, he should be obliged to do it, or perish for want: but his meaning is, that though he preached the Gospel ever so well, or ever so freely, and might glory before men, and against the false teachers, who insulted him in his character and office; yet not before God, from whom he received all his gifts, abilities, and qualifications, to preach the Gospel; all his light and knowledge in it; all his enlargements in meditation, and liberty in expression; all his faithfulness and integrity, courage and intrepidity, in the discharge and performance of his work, were by divine grace and assistance; and his success in it owing to the power and Spirit of God, so that he had nothing to glory of on any of these accounts: hence these words are a correction, or rather an explanation of the preceding:

for necessity is laid upon me;
not of getting a livelihood by preaching, for he could have got, and did get this another way, even by labouring with his hands; nor of force and compulsion, for no one more readily engaged in it, or more cheerfully performed it; but of obligation from the divine call to this work, and from his own conscience, in which he knew it to be an heavenly one, and from the nature of the trust committed to him, and because of the good of immortal souls, and the honour of Christ; all which lay with weight upon him, and obliged him in duty, love, and gratitude, to attend to it:

yea, woe is unto me, if I preach not the Gospel;
which is to be understood, not of any temporal affliction, as reproach, persecution, famine, nakedness, sword for such sort of woes frequently attend those that do preach the Gospel; but of the wounding of his conscience, and exposing himself, through the neglect of his calling, and contempt of the divine will, to the wrath and curse of God for ever; not that the apostle feared this would be his case, or that it possibly could be; but he thus speaks, to show what he or any other minister of the Gospel would deserve, at the hand of God, who having abilities to preach, should not make use of them; or should preach, but not the Gospel; or only a part of it, and not the whole; or should entirely desist from it, through self-interest, or the fear of man, or through being ashamed of Christ and his Gospel, or as not able to bear the reproach and persecution attending it.